JP3357579B2 - Blocker device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for manufacturing a semiconductor device by transferring a mask pattern onto a wafer and, more particularly, to a blocker apparatus capable of exposing an arbitrary exposure area by blocking exposure light. , SOR using synchrotron radiation and X-ray exposure equipment with short exposure wavelength
The present invention relates to a blocker device suitable for use in an exposure device.

[0002]

2. Description of the Related Art In the manufacture of semiconductor integrated circuits, when a mask pattern is transferred to a resist applied on a wafer by an exposure device, a portion of exposure light is blocked by a blocker device to limit the exposure area of the wafer. I have. Such a blocker device includes a plurality of blockers that block a part of the exposure light, and a blocker positioning mechanism that moves these blockers and positions them at a predetermined position. The blocker blocks only the exposure light. A method has been proposed in which alignment light used to align a mask and a wafer is made of a transparent material (eg, Japanese Patent Publication No. 1-144221).

The size of patterns formed on semiconductors is becoming increasingly smaller, and the wavelength of exposure light for transferring patterns has become shorter than 200 nm, such as excimer lasers. In addition, the alignment light used for alignment has a wavelength of 600 nm or more, and it is easy to separate them. Also, the alignment light
In order to obtain detection accuracy, a laser having a narrow wavelength band is often used.

FIG. 3 is a sectional view showing the structure of a conventional blocker device used in an X-ray exposure apparatus, and FIG. 4 is a plan view of the blocker. In these figures, reference numeral 1 denotes a mask on which a pattern (mask pattern) 1a as an original to be transferred is formed;
Reference numerals a to 2d denote a blocker that shields the exposure light L1 and allows the alignment light L2 to pass therethrough. The blockers are arranged in parallel in the X and Y directions with the exposure light L1 interposed therebetween so as to be viewed in plan as a whole. It is arranged in a letter shape. Further, the blockers 2a to 2d are formed of plates having a constant thickness, and are positioned by mutually opposing parallel ones being moved toward and away from each other by the blocker positioning mechanism 3, and the exposure light for irradiating the mask 1 is provided. Shape L1 to the desired size. The blockers 2a to 2d each include a normal mask 1,
It is installed so as to be parallel to the wafer 4 and the positioning mechanism 3 and perpendicular to the optical axis of the alignment light L2. This is to minimize the optical path in the blockers 2a to 2d and minimize the attenuation. The drive source of the blocker positioning mechanism 3 is a D with a rotary encoder.
A C servomotor or the like is used. Alignment light L2
As described above, light having a wavelength longer than the exposure light L1 is used, and after passing through the blockers 2a to 2d, the alignment pattern formed on the mask 1 and the wafer 4 is irradiated.

[0005] Reference numeral 5 denotes an alignment optical system for detecting the relative position between the mask 1 and the wafer 4 using the alignment light L2;
Denotes a mask stage on which the mask 1 is mounted, and 7 denotes a wafer stage on which the wafer 4 is mounted.

The mask 1 on which a mask pattern 1a to be transferred is formed is mounted on a mask stage 6 arranged below the blockers 2a to 2d. Blocker 2a
Exposure light L1 shaped into a desired shape by being partially shielded by .about.2d irradiates the device region on the mask 1, and the exposure light transmitted therethrough irradiates the resist applied on the wafer 4. Exposure causes the mask pattern 1a to be transferred.

Since the blockers 2a to 2d block a part of the exposure light L1 and transmit the alignment light L2, the mask 1 and the wafer 4 can always be directly detected even during exposure by using the alignment light L2. . For this reason, there is an advantage that misalignment due to thermal deformation or the like can be corrected and highly accurate alignment can be performed.

[0008]

However, in the above-mentioned conventional blocker device, the blockers 2a to 2d
Is arranged so as to be perpendicular to the optical axis of the alignment light L2, so that the reflected light reflected on the surfaces of the blockers 2a to 2d returns to the alignment optical system 5 through the original optical path, and this reflected light In addition, there is a problem that the alignment light beams detected by the alignment optical system 5 after irradiating the alignment pattern of the mask 1 and the wafer 4 interfere with each other, thereby lowering the alignment accuracy. Further, since the blockers 2a to 2d are parallel to the mask 1 and the wafer 4, multiple reflections occur between the blockers 2a to 2d and the mask 1 or the wafer 4, and when they enter the alignment optical system 5, they interfere with the alignment light. Further lower the alignment accuracy. Therefore, in order to improve the alignment accuracy, it is strongly necessary to take measures to minimize the reflected light from the blockers 2a to 2d and the multiple reflected light between the blockers 2a to 2d and the mask 1 or the wafer 4 as described above. Was desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a blocker device which eliminates the influence of reflected light and improves the alignment accuracy between a mask and a wafer. To provide.

[0010]

In order to achieve the above object, the present invention provides a plurality of blockers for blocking exposure light for transferring a pattern of a mask onto a wafer in order to limit an exposure area of the wafer. A positioning mechanism for moving the blocker to shape the exposure area into a desired shape, the blocker being made of a material that blocks the exposure light but transmits the alignment light used to align the mask and the wafer. In the apparatus, the block of alignment light
The light reflected by the locker does not return to the alignment optical system.
The thickness of the blocker is changed . In the present invention, the reflected light reflected on the surface of the blocker
Is different from the incident direction because the thickness of the blocker is different
Reflected by the alignment optics.
Never be. Blockers are also used for masks and wafers.
After irradiating C, it reflects the light that has returned and reflected.
The reflection direction is different from the incident direction to the blocker.
There is no multiple reflection between the masker and the mask or wafer.
No. Therefore, the reflected light or mask reflected on the mask surface
Multiple reflection light between the disk or wafer and the blocker
Light does not interfere with each other, improving alignment accuracy.
Can be up.

[0011]

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a sectional view showing an embodiment of the blocker device according to the present invention. In addition,
The same components as those shown in the section of the prior art are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
In the present embodiment, four blockers 2a to 2d (2b and 2d are not shown) for limiting the exposure area, which are arranged two by two in the X and Y directions, respectively, are arranged on the optical axis of the alignment light L2. It is provided to be inclined with respect to.

The blockers 2a to 2d are made of a material that blocks the exposure light L1 and transmits the alignment light L2. Specifically, any material having a certain thickness, such as quartz glass, mica, glass, and diamond, can be used. X-rays are used as the exposure light L1, but ultraviolet rays having a longer wavelength than the X-rays may be used. it can. The blocker positioning mechanism 3 includes two blockers 2a and 2c facing each other,
Blockers 2a to 2d in a direction where 2b and 2d approach each other.
Can be adjusted in the same manner by rotating in the rolling direction (vertical direction in the figure) with respect to the moving axis.

In this embodiment, the blockers 2a to 2a
The blockers 2a to 2d are tilted so that the inner edge that blocks the exposure light L1 of 2d is lower than the outer edge fixed to the blocker positioning mechanism 3, in other words, approaches the mask 1. May be inclined so as to be lower than the inner edge. Thus, the blockers 2a to 2a
When d is inclined, the reflected light of the alignment light L1 reflected on the surfaces of the blockers 2a to 2d is blocked.
Since 2d is inclined, it does not return to the alignment optical system 5 through the original optical path. Also, the reflected light that is reflected by the light returned from the mask 1 and the wafer 4 and hits the back surfaces of the blockers 2a to 2d does not return to the mask 1 or the wafer 4 because the blockers 2a to 2d are inclined. Or the wafer 4 and the blockers 2a-2
Multiple reflection between d can be prevented.

FIG. 2 is a sectional view showing another embodiment of the present invention. In this embodiment, the blockers 2a to 2a
By forming 2d by a plate having a wedge-shaped cross section, the thickness is gradually changed in the width direction, and the inner edge has the minimum thickness and the outer edge has the maximum thickness. For this reason, the front and back surfaces are inclined in opposite directions. However, the thickness may be maximum at the inner edge and minimum at the outer edge.

Even in such a configuration, the blocker 2a
2d are inclined, so that even if the alignment light L1 radiated from the alignment optical system 5 is reflected by the surface of the blockers 2a to 2d, the reflected light is originally Is not detected by the alignment optical system 5 through the optical path. The light reflected from the mask 1 and the wafer 4 and returned from the blockers 2a to 2a.
The light reflected on the back surface of 2d is also reflected on the mask 1 or the wafer 4
And multiple reflection between the mask 1 or the wafer 4 and the blockers 2a to 2d can be prevented.

Next, as a third embodiment, when light having a limited wavelength band, such as laser light, is used as the alignment light L2, a non-reflective coating that does not reflect the alignment light L2 is formed on the front and back surfaces. Blocker 2a applied
To 2d may be arranged perpendicular to the alignment light L2. When the non-reflection coating is applied, the reflected light of the alignment light L2 from the blockers 2a to 2d can be suppressed small, so that it is not necessary to arrange the blockers 2a to 2b at an inclination or to make the cross-sectional shape wedge-shaped. The conventional blocker shown in FIGS. 3 and 4 can be used.
However, it is a matter of course that the blockers 2a to 2d according to the present invention shown in FIG. 1 or FIG. Further, the light reflected from the mask 1 or the wafer 4 is used for the blocker 2a.
The light reflected by .about.2d and returning to the mask 1 or the wafer 4 is also very weak due to the non-reflective coating, and the same effect as in the above embodiment can be obtained.

[0019]

As described above, according to the blocker apparatus of the present invention, the light reflected on the surface of the blocker does not pass through the original optical path and is not detected by the alignment optical system. The light reflected by the wafer and reflected by the blocker does not return to the mask or wafer, and multiple reflection between the mask or wafer and the blocker can be prevented. Therefore, the alignment light and the reflected light reflected on the mask surface or the reflected light multiple-reflected between the mask or the wafer and the blocker do not interfere with each other, and the alignment accuracy can be improved.

[0020]

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a blocker device according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the blocker device according to the present invention.

FIG. 3 is a sectional view showing a conventional example of a blocker device.

FIG. 4 is a plan view of a blocker.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mask, 1a ... Mask pattern, 2a-2d ... Blocker, 3 ... Blocker positioning mechanism, 4 ... Wafer, 5 ... Alignment optical system, 6 ... Mask stage, 7 ... Wafer stage, L1 ... Exposure light, L2 ... Alignment light .

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-7-326574 (JP, A) JP-A-4-65110 (JP, A) JP-A-7-283124 (JP, A) JP-A-7-283 226352 (JP, A) JP-A-6-291018 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027

Claims (1)

(57) [Claims] 1. A plurality of blockers that block exposure light for transferring a mask pattern onto a wafer in order to limit an exposure area of a wafer, and a positioning mechanism that moves these blockers to shape the exposure area into a desired shape. In a blocker device made of a material that blocks the exposure light but blocks the exposure light but transmits the alignment light used for aligning the mask and the wafer , the reflected light of the alignment light reflected by the blocker is reflected by the blocker.
Change the thickness of the blocker so that it does not return to the
A blocker device characterized by being made into a blocker.